1. A draw-works for raising and lowering a drill head, the draw-works comprising:
a base;
at least three hydraulic cylinders positioned between the first end and the second end of the draw-works, the at least three hydraulic cylinders each comprising a rod and a piston;
a plurality of braces connecting the at least three hydraulic cylinders; and
a carriage mounted to the at least three hydraulic cylinders,
wherein the rod of at least one of the at least three hydraulic cylinders is oriented towards a first end of the draw-works, and the rod of at least another of the at least three hydraulic cylinders is oriented towards a second end of the draw-works, and wherein the drill head is mounted to the carriage.
2. The draw-works of claim 1, wherein the plurality of braces each comprise at least three apertures, and wherein the at least three hydraulic cylinders are positioned through the plurality of braces.
3. The draw-works of claim 1, further comprising a plurality of guide beams, wherein the carriage and the plurality of braces are positioned between the plurality of guide beams.
4. The draw-works of claim 3, wherein each brace of the plurality of braces each comprises a plurality of guide wheels, wherein each of the respective plurality of guide wheels is positioned within a respective plurality of guide beams to allow the braces to move vertically.
5. The draw-works of claim 3, wherein the carriage comprises a plurality of guide wheels, wherein each of the plurality of guide wheels is positioned within a respective plurality of guide beams to allow the carriage to move vertically.
6. The draw-works of claim 1, wherein the rod of the at least one of the at least three hydraulic cylinders supplies hydraulic fluid through a plurality of conduits adapted for communicating hydraulic fluid therethrough.
7. The draw-works of claim 6, wherein the at least one of the at least three hydraulic cylinders is in fluid communication with the remainder of the at least three hydraulic cylinders, and the remainder of the at least three hydraulic cylinders receives hydraulic fluid through the at least one of the at least three hydraulic cylinders.
8. The draw-works of claim 7, wherein a manifold enables fluid communication between the at least three hydraulic cylinders.
9. The draw-works of claim 8, wherein the manifold comprises a first plurality of control valves and a second plurality of control valves, wherein the first plurality of control valves allows a higher flow rate than the second plurality of control valves.
10. The draw-works of claim 8, wherein the manifold comprises a plurality of check valves in communication with the plurality of conduits.
11. The draw-works of claim 1, wherein each of the at least three hydraulic cylinders further comprise a potentiometer for measuring vertical movement of the corresponding rod.
12. The draw-works of claim 1, wherein each of the at least three hydraulic cylinders further comprise a cushion spear.
13. The draw-works of claim 1, wherein the carriage and the drill head are connected through a crown wheel assembly.
14. The draw-works of claim 13, wherein the crown wheel assembly comprises a kevlar belt mounted on a spool, wherein the spool is mounted on the carriage, and wherein the kevlar belt is affixed to the drill head.
15. A method of raising and lowering a drill head mounted on a plurality of hydraulic cylinders, the method comprising:
actuating a first plurality of control valves within a manifold to communicate hydraulic fluid from a pressurized fluid source into at least one central hydraulic cylinder;
actuating a second plurality of control valves within a manifold to prevent fluid communication between the at least one central hydraulic cylinder and at least one outer hydraulic cylinder;
allowing the at least one central hydraulic cylinder to reach a top of stroke;
actuating the second plurality of control valves to allow fluid communication between the at least one central hydraulic cylinder, the at least one outer hydraulic cylinder, and a storage tank;
allowing the at least one outer hydraulic cylinder to reach a top of stroke;
actuating the second plurality of control valves to prevent fluid communication between the pressurized source and the at least one outer hydraulic cylinder;
allowing the at least one outer hydraulic cylinder to retract;
actuating the first plurality of control valves to prevent fluid communication between the pressurized source and the at least one central hydraulic cylinder; and
allowing the at least one central hydraulic cylinder to retract.
16. The method of claim 15, further comprising the step of mounting a potentiometer along the plurality of hydraulic cylinders.
17. The method of claim 15, further comprising the step of actuating a third control valve in fluid communication with a hydraulic accumulator to permit fluid communication between the hydraulic accumulator and the pressurized fluid source.
18. The method of claim 17, further comprising the step of actuating the third control valve to permit fluid communication between the hydraulic accumulator and the storage tank.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A positive engagement clutch having a torque input side and a torque output side, the clutch comprising a torque input member arranged on the torque input side, a torque output member arranged on the torque output side, first engagement members, second engagement members, and an actuator, the torque input member and the torque output member being arranged concentrically to rotate on a common axis, one of the torque input member and the torque output member carrying the first engagement members, and the other of the torque input member and the torque output member carrying the second engagement members, the first engagement members being radially movable by the actuator between a projecting and a retracted position, and the second engagement members projecting radially into a gap between the torque input member and the torque output member, the first and second engagement members engaging with each other, when the first engagement members are in the projecting position, to progressively engage the torque input and output members to allow the transmission of torque to the torque output side, and the first and second engagement members being disengaged from each other, when the first engagement members are in the retracted position, to prevent the transmission of torque to the torque output side.
2. A positive engagement clutch as claimed in claim 1, wherein the first and second engagement members are in the form of ball-bearings.
3. A positive engagement clutch as claimed in claim 1, wherein the first and second engagement members are in the form of rollers.
4. A positive engagement clutch as claimed in claim 1, wherein the actuator is in the form of a push-rod element having a frusto-conical portion along which the first engagement members can move to take up the projecting position or the retracted position.
5. A positive engagement clutch as claimed in claim 1, wherein the first engagement members are free to move independently of each other.
6. A positive engagement clutch as claimed in claim 1, wherein the second engagement members are free to move independently of each other.
7. A positive engagement clutch as claimed in claim 1, wherein the first engagement members are carried by the torque output member, and the second engagement members are carried by the torque input member.
8. A positive engagement clutch as claimed in claim 1 in combination with a rotary coupling, the rotary coupling comprising a driving part, a drivable part, a fixed part in which the driving and drivable parts are each rotatable coaxially, and a set of coupling members carried by one of the driving and drivable parts for torque-transmitting engagement with the other, the coupling members being selectively positionable so that, in a first condition, the coupling members are juxtaposed to a primary annular contact surface of either the fixed part or the drivable part and, in a second condition, the coupling members are juxtaposed to a secondary annular contact surface of the driving part, each coupling member being free to move relative to the driving and drivable parts into and out of engagement with the primary and secondary annular contact surfaces, the arrangement being such that, when the coupling members are in the first condition, the application of a first torque on the coupling members causes the coupling members to engage the primary annular contact surface and, when the coupling members are in the second condition, the application of a second torque on the coupling members causes the coupling members to engage the secondary annular contact surface.